Search

This paper introduces a novel technology for the monolithic integration of GaN-based vertical and lateral devices. This approach is groundbreaking as it facilitates the drive of high-power GaN vertical switching devices through lateral GaN HEMTs with minimal losses and enhanced stability. A significant challenge in this technology is ensuring electrical isolation between the two types of devices. We propose a new isolation method designed to prevent any degradation of the lateral transistor's performance. Specifically, high voltage applied to the drain of the vertical GaN power FinFET can adversely affect the lateral GaN HEMT's performance, leading to a shift in the threshold voltage and potentially compromising device stability and driver performance. To address this issue, we introduce a highly doped n+ GaN layer positioned between the epitaxial layers of the two devices. This approach is validated using the TCAD-Sentaurus simulator, demonstrating that the n+ GaN layer effectively blocks the vertical electric field and prevents any depletion or enhancement of the 2D electron gas (2DEG) in the lateral GaN HEMT. To our knowledge, this represents the first publication of such an innovative isolation strategy between vertical and lateral GaN devices. [ABSTRACT FROM AUTHOR]

N-doped homo-epitaxial GaN samples grown on freestanding GaN substrates have been investigated by micro-Raman spectroscopy. Quantitative analysis of the E 2 h and the A1(LO) modes' behavior has been performed while intentionally increasing the carrier density using silicon doping. We noticed that as the carrier concentration increases up to 1.8 × 1018 cm−3, the E 2 h mode remains unchanged. On the other hand, when the doping gets higher, the A1(LO) position shifts to a higher frequency range, its width becomes larger, and its intensity drastically diminishes. This change in the A1(LO) behavior is due to its interaction and its coupling with the free negative charge carriers. Furthermore, we calibrated the A1(LO) frequency position shift as a function of the n-carrier concentration. We found out that for low n doping, the change in the A1(LO) position can be considered as a linear variation while in the overall doping range, a sigmoid growth trend with a Boltzmann fit can be tentatively applied to describe the A1(LO) position shift. This calibration curve can also be used to describe the coupling strength between the carriers and the A1(LO) phonon. Eventually, this study shows that micro-Raman spectroscopy is a powerful non-destructive tool to probe the doping concentration and the crystalline quality of GaN material with a microscopic spatial resolution. [ABSTRACT FROM AUTHOR]

Diamond is a promising material for future high-voltage applications because of its high critical electric field. This property leads to new constraints on the used termination structure, especially in terms of an electric field value. For this reason, new termination architectures based on a field plate are proposed for diamond Schottky diodes. Using the finite-element simulations with the Sentaurus technology computer-aided design software, a new field plate structure has been proposed. Simple variations in the classic field plate architecture were sufficient to increase the breakdown voltage from 1632 to 2141 V at 700 K, but not to reduce the electric field value at the edges of the field plate. Several termination topologies have been proposed to solve this problem. Parametric simulations were used to optimize the geometrical termination structure in order to reduce the electric field peak value at its edge while maintaining a high breakdown voltage. The new solutions have helped to reduce the maximum electric field from 57 down to 22.7 MV/cm. [ABSTRACT FROM AUTHOR]

Power metal‐oxide semiconductor field effect transistors (MOSFETs) are more and more used in atmospheric and space applications. Thus, it is essential to study the influence of the natural radiation environment on the electrical behaviour of vertical double‐diffused metal‐oxide semiconductor (VDMOS) and super‐junction (SJ) MOSFETs. Two‐dimensional numerical simulations are performed to define the sensitive volume and triggering criteria of single‐event burnout (SEB) for VDMOS and SJ MOSFETs for different configurations of ionising tracks. The analysis of the results allows a better understanding of the SEB mechanism in each structure and allows the behaviour and robustness comparison for these two technologies under heavy‐ion irradiation. [ABSTRACT FROM AUTHOR]

In high current, high voltage, high temperature (T>125^\circC) power applications, commercially available conventional silicon thyristors are not suited because they present high leakage current. In this context, this paper presents a high-symmetrical (voltage) thyristor structure that presents a lower leakage current and higher breakover voltage as compared with the conventional thyristor at T>125^\circC. It is shown through 2-D physical simulations that the replacement of the P-emitter of a standard symmetrical thyristor by a judicious association of P diffusions and Schottky contacts at the anode side contributes to the reduction of the leakage current in the forward blocking state at high temperature. A fine tune of the anode side configuration will improve the forward OFF-state behavior with only a negligible ON-state voltage drop degradation. Moreover, the comparison with the conventional anode short thyristor shows that the insertion of Schottky contacts leads to the same improvements in terms of OFF-state forward breakover voltage and leakage current and also presents a high reverse blocking voltage. [ABSTRACT FROM PUBLISHER]